The present invention relates to a device for extruding an expandable dough for confectionery from plural openings of the device to prepare expanded confectionery (sticks). More particularly, the invention relates to a device for distributing the expandable dough formed at a terminal end of a rotor in an extruder to the plural openings.
As extruders for preparing expanded confectioneries, in general, a single or twin screw type device has been employed, and each device comprises a screw(s) which shall be referred to in this Description as xe2x80x9crotor(s)xe2x80x9d, a barrel and a device for distributing an expandable dough, which has openings for expanding the dough. A starch raw material fed into the extruder from a raw material feeding port at a beginning end of the rotor is heated, pressurized, and subjected to shear force by the rotor in the barrel to gelatinize the material and make it into the expandable dough. The dough is then fed to the openings of the dough distributing device arranged at a terminal end of the rotor and expands whereby the expanded confectionery is prepared.
In such conventional apparatuses for preparing expanded confectioneries, a portion of each dough distributing device has a structure as shown in FIGS. 6 or 7.
The dough distributing device shown in FIG. 6 comprises a flat plate or disc B arranged at a terminal end of a rotor A and having through hole B1 at a central portion thereof, a diverging member C to distribute an expandable dough together with the flat plate, and an opening forming plate D fixed to a terminal end of the diverging member and having plural openings D1. However, the expandable dough dwells on inner wall C1 of the diverging member C, which is arranged opposite to the through hole B1 and the vicinity thereof to cause thermal scorching phenomenon, whereby an amount of the dough flowing into each of the plural openings D1 changes. This means that each of the expanded confectioneries obtained by the expanded confectionery preparing apparatus provided with such a dough distributing device is not uniform in quality thereof.
The dough distributing device shown in FIG. 7 is structurally different from that shown in FIG. 6 in that a cavity B2 is formed in a rotor-side surface of a flat plate or disc B arranged at the terminal end of a rotor A and having a through hole B1, in that the structure of the diverging member is simplified, and in that plural openings C2 are formed in the diverging member per se. In this dough distributing device, an expandable dough for confectionery passed the through hole B1 is uniformly and spreadingly fed to the plural openings C2, by actions of an outer wall of the flat plate B and the inner wall of the diverging member C, and is distributed to the openings. However, a phenomenon similar to that occurring in the dough distributing device shown in FIG. 6 occurs and the expandable dough for confectionery dwells on the inner wall C1 of the diverging member C and a vicinity thereof, and each of the expanded confectioneries formed through plural openings is not so uniform in quality.
In Japanese Patent 62-259538(A) as one of patent literatures, there is disclosed a screw extruder for extrudingly preparing various foods by supplying thereto raw material dough. An extruding passage is diverged into plural diverging passages, each having the same shape and the same length, and a food extruding die is fixed to each tip end of the diverging passage. When the extruder is applied for preparing an expanded confectionery, uniformity in the overall quality of the products shall be improved, but non-uniformity in the quality of each expanded confectionery formed though each of the extruding holes in the die can still not be overcome.
In Japanese Patent 61- 19445(A), further, an xe2x80x9capparatus for preparing expanded snack confectioneryxe2x80x9d has been disclosed. A dough distributing device for the apparatus is shown in FIG. 8. The dough distributing device has a structure such that a flat plate F is arranged between a rotor A of a single screw extruder and a die portion E, with a slight gap from tip end of the rotor. The flat plate has a through hole F1 at a central portion thereof and a dough guiding cavity F2 at a die side surface to communicate the through hole with die openings E1. When the apparatus for preparing expanded snack confectionery and provided with the dough distributing device is employed, uniformity in the overall quality of the products can be improved, but if depth T of the dough guiding cavity is different from diameter W of each of the die openings, non-uniformity in quality is still present between the expanded confectioneries formed through plural die openings.
Therefore, an object of the invention is to provide a device for distributing an expandable dough for confectioneries, which drastically reduces non-uniformity in quality of each of expanded confectioneries extrudingly and concurrently formed through each of plural openings at terminal end of an extruder.
Fundamentals of the invention lie in immediately diverging flow of an expandable dough passed through rotor portion of a single or twin rotor extruder, and feeding each of the expandable dough flows to a relative opening to cause expansion of the dough for preparing a desired expanded confectionery.
Therefore, a device for distributing dough in an extruder according to the invention includes a first member arranged near a terminal end of a rotor in the extruder, and the first member has a through hole for the expandable dough at a central portion thereof and has radial channels which communicate with the through hole. A second member is connected to the first member, and has bores corresponding in number to the number of radial channels in the first member and arranged so as to form a concentric circle. The second member has an inner wall with a multi-faced pyramid-like projection on a central portion of the inner wall, and the inner wall has radial channels extending from the base of the projection. Each free end of the radial channels communicate with each end of the bores. The radial channels in the first member and the radial channels in said second member are opposingly arranged in alignment to form diverging flow passages for the expandable dough, and the sectional size of the diverging flow passage is the same as that of the bore formed in the second member.
According to the dough distributing device of the invention, each of the radial channels formed in the first and second members is oppositely arranged in alignment to form diverging flow passages for the expandable dough, and each end of the diverging flow passages communicates to each end of the bores formed in the second member. Thus, there is no portion for causing the expandable dough that has passed the through hole formed in the first member to dwell. Therefore, an amount of the expandable dough extruded from each free end of the bores becomes substantially the same, so that the quality of the expanded confectioneries obtained through each of the bores shall become uniform.
If a somewhat thick end plate formed with through holes somewhat large in diameter is attached to the outer wall of the second member, the state of the expanded confectionery becomes more preferable.